Virgin Galactic spacecraft appears to have broken apart in flight

Debris from the crashed Virgin Galactic SpaceShipTwo craft is shown in this video still.

The head of the federal agency examining last week's fatal crash of a Virgin Galactic passenger spaceship during a test flight in California's Mojave Desert said on Sunday the vehicle appears to have broken apart in flight.

"The debris field indicates an in-flight breakup," Christopher Hart, acting chairman of the National Transportation Safety Board, told Reuters during a interview.

"We'll know that for certainty when we look at all the sources we have," he said.

The NTSB is leading the investigation into Friday's crash of SpaceShipTwo, which was undergoing its first powered test flight since January when it crashed, spreading debris over a 5-mile (8 kilometers) swath of the Mojave Desert north of Los Angeles.

SpaceShipTwo was in the midst of test flights and was not yet certified for commercial operations when the crash occurred, delaying indefinitely the start of passenger service.

Branson and his son plan to fly on the first commercial flight. About 800 people already have paid or put down deposits for the ride, which costs $250,000.

The craft is intended to fly people to an altitude of just over 60 miles (100 kilometers) so they can experience a few minutes of weightlessness and see the Earth against the blackness of space.

"We really thought by March of next year, we'd be there," the billionaire entrepreneur told the BBC after arriving in Mojave on Saturday. "Something went wrong. We need to find out what went wrong and fix it."

U.S. investigators say the powered test flight of Virgin's SpaceShipTwo on Friday was well recorded, giving them an abundance of information to help determine what caused the rupture.

The two pilots involved were employees of Scaled Composites, a Northrop Grumman subsidiary that designed and built the six-passenger, two-pilot craft for Virgin Galactic.

Michael Alsbury, 39, was identified as the pilot who died. Co-pilot Peter Siebold, 43, who was riding in the right-hand seat, parachuted to the ground and was recovering at a nearby hospital, Scaled Composites said in a statement.

Friday's crash was the second disaster in less than a week suffered by a private space company.

On Tuesday, an Antares rocket built and launched by Orbital Sciences exploded after liftoff from Wallops Island, Virginia, destroying a cargo ship bound for the International Space Station.

Virgin Galactic is a U.S. offshoot of the London-based Virgin Group founded by Branson, whose empire ranges from airlines to music stores and mobiles phones.